William, also known as Burntrap, miraculously escapes the clutches of The Blob and manages to defeat it using his Remnant power, which he obtained by killing children with the help of his brainwashed follower, Vanny. Now, as the underground pizzeria is engulfed in flames after being thwarted by a child named Gregory and his animatronic companion, Glamrock Freddy, whom he despises and desires to kill, William's priority is to flee. Recalling the secret passage he instructed Vanny to prepare as an escape route in case of failure, he navigates through the cramped cave passage, albeit annoyingly, but ultimately emerges freely.

After spending numerous years trapped in the underground pizzeria, originally set up by his former friend and co-owner, Henry Emily, and his older son, Michael Afton, in an attempt to end the curse he initiated, William Afton remains determined to fulfill his ambitions and grow even more powerful than he ever imagined. As he observes the Mega Pizzaplex being engulfed by flames, he retreats into the darkness, still carrying a knife within his decayed and withered body, ready to defend himself or strike anyone who crosses his path.

Ahead of him, Burntrap spots a road with a parked truck nearby. The truck's shutter door is open, revealing boxes stacked inside, providing him with the perfect cover. Quietly, he slips into the truck and conceals himself among the cargo. Soon after, two men return from a nearby gas station, closing the shutter door and starting the truck's engine. As the vehicle begins to move, Burntrap leans against the wall, feeling the slight bounce of the moving truck. Despite the movement, he feels a sense of safety as the truck travels away from Utah in Washington County.

After hours of driving, they arrived in the city of Canterlot as night began to fall. Parking near an unfamiliar store, one of the men went to open the shutter door, only to be surprised by Burntrap, who swiftly snapped his neck. Hearing the commotion, the truck driver stepped out to check on his friend, only to discover his lifeless body, leaving him in shock. Before he could react, Burntrap appeared behind him and stabbed him in the neck. With the witnesses taken care of, Burntrap hurriedly fled the scene in search of a hiding spot.

After spending several hours on the road inside the truck, he found himself in an unfamiliar area, a place he had never seen before. However, he knew he needed to find a hiding spot. Taking advantage of the cover of darkness, he slipped into the shadows and cautiously made his way through the city. Spotting an abandoned warehouse in a secluded alleyway, he cautiously approached, keeping a tight grip on his knife. Seeing no signs of danger, he entered the warehouse, intending to make it his temporary shelter.

The warehouse was cluttered with gears, mechanical parts, and other machinery-related items. As he wandered through the room, a peculiar sensation washed over him. Turning towards a nearby door, he cautiously pushed it open, revealing a large mirror hanging on the wall. Approaching it slowly, he could only see his own reflection staring back at him. Anger boiled within him as he beheld the decayed, burned, and withering animatronic suit that had become his prison. Recalling the events that led to his transformation from Springtrap to Burntrap, he felt a surge of frustration. Trapped in a digital hell orchestrated by Cassidy, also known as Golden Freddy, he had endured countless trials and tribulations as revenge for the pain and suffering he had caused. Now, defeated by a child and his animatronic companion, he seethed with rage. Uncertain of Vanny's fate, he let out a roar of frustration and attempted to strike the mirror, only to watch his fist pass through it as if by magic. Surprised by this phenomenon, he withdrew his hand and examined it closely before tentatively touching the mirror again. Intrigued by its inexplicable properties, he resolved to investigate further. Driven by curiosity, he stepped through the mirror and found himself transported to a different world.

...

World of Equestria

Emerging from the mirror, Burntrap's eyes widened in shock as he surveyed the dilapidated surroundings. Cracks marred the walls and floor, while cobwebs draped the corners of the ceiling. Although there were bookshelves lining the room, he decided to explore them later. Uncertain of his current location, he glanced back at the mirror before making his way to the door and stepping into the hallway. Exiting into the corridor, he found himself standing in the ruins of a castle adorned with banners depicting symbols of alicorns representing the sun and moon. Puzzled by his surroundings, he cast his gaze around, pondering the nature of this unfamiliar world. Suddenly, the distant sounds of battle caught his attention. Intrigued, he resolved to investigate further and set off towards the source of the commotion without hesitation.

As he ventured deeper into the forest, Burntrap encountered a sight that left him astonished. A group of wolf-like creatures, known as Timberwolves, emerged from the shadows and prepared to attack. Reacting swiftly, Burntrap defended himself as one of the Timberwolves lunged at him. In a surprising turn of events, Burntrap discovered that he possessed the ability to control organic beings, a power he had previously been unaware of, as his abilities had previously only worked on animatronics. Taking advantage of this newfound ability, Burntrap managed to assert control over the pack of Timberwolves, making them obedient to his commands. With the Timberwolves under his control, Burntrap pressed on through the forest, eventually arriving at his destination where he was met with a startling sight.

Witnessing a group of mythical sentient creatures arrive to assist the female ponies in their battle against three villains—a former changeling queen, a power-hungry demon-like centaur, and a malevolent filly pony with dark powers—Burntrap opted to remain hidden in the forest, observing the unfolding events from afar. As the villains were ultimately defeated and turned to stone by Celestia, Luna, and Discord, Burntrap decided he had seen enough and swiftly made his escape.

Upon his return to the ruined castle, Burntrap expanded his control over more monster creatures encountered, commanding them to guard the castle and repel intruders while he delved into the underground library in search of valuable resources. There, he stumbled upon a book detailing the study of dark magic, particularly focusing on the magic wielded by King Sombra from thousand of years ago. Over the course of several weeks, Burntrap devoted himself to studying the dark arts, conducting experiments day and night to explore the potential of combining Remnant and dark magic to attain unimaginable power. After numerous trials and errors, he successfully harnessed this combined power, using it initially to restore himself.

This initial action marked the beginning of a transformation, during which his entire body underwent a significant alteration. Following the transformation, he assumed the form of Glitchtrap, a malevolent digital AI whose soul had been trapped in a virtual reality environment until Vanessa, acting as a Beta Tester, unwittingly became a brainwashed follower for him to exert his influence and carry out his commands.

Upon beholding his Glitchtrap form, he erupted into manic laughter, the sound echoing throughout the underground. Spreading his arms wide, he spoke to himself in a dark tone, his expression twisted into an excited and malevolent smile.

Glitchtrap: I ALWAYS COME BACK!!!

AHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA!